This invention relates to inkjet printers and the like and, more particularly, to an ink container having mechanical and electronic features that allow different sizes of ink containers to be plug compatible while providing an automatic and accurate way of tracking ink remaining in the ink container.
Ink-jet printers or printing systems frequently make use of an ink-jet printhead mounted to a carriage which is moved back and forth across a print media, such as paper. As the printhead is moved across the print media, control electronics activate the printhead to eject, or jet, ink droplets onto print media to form images and characters.
Some printing systems make use of an "off-carriage" or "off-axis" ink container that is replaceable separately from a high performance printhead wherein the ink container is located off of the carriage. When the ink container is exhausted the ink container is removed and replaced with a new ink container. The use of replaceable ink containers that are separate from the printhead allow users to replace the ink container without replacing the printhead and allows for larger ink supplies than would be practical on a scanning carriage. The printhead is then replaced at or near the end of printhead life and not when the ink container is exhausted. This tends to lower the average cost per printed page for the system and can decrease the frequency of ink container replacement.
Generally, the frequency of replacement of ink containers is determined by the initial volume of ink held in the ink containers and the rate of consumption of the ink. An ink container that is smaller requires more frequent ink container replacement for a given usage rate. This can be inconvenient to the user. A related problem occurs if the printer runs out of ink while printing a document. When this happens, the user must reprint at least part of the printed document. This results in wasted ink and media. With a combination of high use rate printing and small ink containers, running out of ink and reprinting documents can become a very frequent event, resulting in considerable inconvenience and waste of ink and media.
The use of a larger ink container results in a less frequent ink container replacement for a given usage rate. If the container is too large, the container may reside in the printer beyond the ink shelf life. When this happens, the user must decide between replacing the container or using the ink. Replacing the container implies throwing away unused ink. On the other hand, using old ink may damage the printhead or printer. Thus, too large of an ink container will at least negatively impact cost per printed page and/or printing system reliability.
Accordingly, it is desirable to have inkjet printing systems that conveniently, reliably, and cost-effectively accommodate a range of ink usage rates.